#include <iostream>
#include <vector>
#include <list>

class Single {
private:
    Single() {
        std::cout << "single!!\n";
    }
public:
    static Single* getInstance() {
        static Single eton;
        return &eton;
    }
    void print() {
        std::cout << "xxxx\n";
    }
};

int main() {
    Single::getInstance()->print();
    return 0;
}
